Information storage devices are used to retrieve and/or store data in computers and other consumer electronics devices. A magnetic hard disk drive is an example of an information storage device that includes one or more heads that can both read and write, but other information storage devices also include heads—sometimes including heads that cannot write.
In a magnetic hard disk drive, the head typically comprises a body called a slider that carries a magnetic transducer on its trailing end. Examples of sliders are described in U.S. Pat. No. 7,872,833, filed Sep. 25, 2007, the contents of which is hereby incorporated by reference in its entirety. The magnetic transducer typically comprises a writer and a read element. The magnetic transducer's writer may be of a longitudinal or perpendicular design, and the read element of the magnetic transducer may be inductive or magnetoresistive. In a magnetic hard disk drive, the transducer is typically supported in very close proximity to the magnetic disk by a hydrodynamic air bearing. As the motor rotates the magnetic disk, the hydrodynamic air bearing is formed between an air bearing surface (ABS) of the slider of the head, and a surface of the magnetic disk. The thickness of the air bearing at the location of the transducer is commonly referred to as “flying height.”
During operation, lubricant is present on the disk and can accumulate on the slider by evaporation or physical contact. During flight, the lubricant follows the shear stress field caused by airflow over the ABS. In some heads, lubricant blockers (for example, the trailing air flow dams described U.S. Pat. No. 7,872,833) extend to the trailing edge of the slider. The lubricant blockers block the majority of lubricant picked up by the ABS, but some lubricant climbs over the blocker and accumulates at the slider trailing end (i.e., the deposit end of the slider). When read/write operations are not occurring, the slider parks on a ramp. While parking on the ramp, the accumulated lubricant at the slider trailing end flows back to the ABS through diffusion. This “lubricant waterfall effect” affects drive recording performance when the head returns to the disk (i.e., is “reloaded”) after extended flying followed by long parking. In particular, the lubricant waterfall effect undesirably increases the initial flying height. The head slowly returns to normal flight height after the lubricant moves back to the trailing end through air flow.